Node device, control device, control method and control program

ABSTRACT

A control device managing a plurality of nodes transmitting and receiving data containing an error correcting code, comprises means accepting, when any one of the nodes detects an uncorrectable error from the data containing the error correcting code, a signal transmitted by the node detecting the error, means judging from a record of the detection of a first node, when accepting the signal from a second node receiving data transmitted by the first node, whether or not the first node has detected the uncorrectable error from the data transmitted to the second node, and means stopping, when the first node has detected the uncorrectable error from the data transmitted to the second node, a process attributed to the acceptance of the signal from the second node.

BACKGROUND OF THE INVENTION

The present invention relates to a control device managing a pluralityof nodes and to a node device cooperating with the control device.

In a system capable of recognizing poisoning data attached touncorrectable data, when an existing node receives the poisoning data, adata packet containing the poisoning data is sent to an existing nodesituated at a posterior stage. Therefore, a fault detection rate isimproved without detecting unnecessary uncorrectable errors. Theuncorrectable data is defined as the data that can not be corrected.Further, the uncorrectable error is defined as the data error that cannot be corrected. “Poisoning” connotes that when the node receives theuncorrectable data, respective bits of an ECC (Error Correcting Code)attached to a tailing part of the data are converted into a specifiedpattern (data). Namely, the poisoning comes under one category of theterm “uncorrectable”.

Data processing can be executed at the existing node at the final stageby flowing the data packet through to the end of the system. In FIG. 1,the uncorrectable error occurs in a bus 1 between an existing node A andan existing node B (which is represented by Occurrence of UE in FIG. 1).In this case, the existing node B receiving the uncorrectable data fromthe existing node A detects the uncorrectable error (which isrepresented by Detection of UE in FIG. 1). Then, the existing node Bexecutes a poisoning process about the ECC attached to the uncorrectabledata, and transmits the data packet containing the poisoning data to anexisting node C.

The existing node C can recognize the poisoning data attached to theuncorrectable data and therefore, even when receiving the data packetcontaining the poisoning data, detects none of the uncorrectable error.Then, the existing node transmits the data packet containing thepoisoning data to an existing node D. Thus, the detection of theuncorrectable error is made by only the existing node B but getsunnecessary in the existing node C and in the existing node D, therebyimproving the fault detection rate.

There has hitherto been a poisoning data recognizing method in a casebased on such a premise of the system that all of the nodes are capableof recognizing the poisoning data attached to the uncorrectable data.

[Patent document 1] Japanese Patent Application Laid-Open PublicationNo. 2004-242294

SUMMARY OF THE INVENTION

In the system capable of recognizing the poisoning data attached to theuncorrectable data, when recognizing the poisoning data midway on aroute within the system, the detection of the uncorrectable error is notconducted. In the case of adding to the system a general-purpose nodeincapable of recognizing the poisoning data attached to theuncorrectable data, however, when the poisoning data passes through thegeneral-purpose node, the uncorrectable error is detected.

Normally, if the uncorrectable error is detected by the general-purposenode, this is pointed as a fault in the general-purpose node or a faultin the bus connected to the general-purpose node. Even if the poisoningdata is attached to the uncorrectable data passing though thegeneral-purpose node, the general-purpose node detects the uncorrectableerror. Namely, the uncorrectable error detected by the general-purposenode does not undergo judgment as to whether the poisoning data isattached to the uncorrectable data or not.

Accordingly, even when the general-purpose node detects theuncorrectable error, it is impossible to distinguish whether or not thepoisoning data is attached to the uncorrectable data passing through thegeneral-purpose node.

Hence, it is unfeasible to judge whether it is the fault in thegeneral-purpose node or the fault in the bus connected to thegeneral-purpose node or a fault in a component other than thegeneral-purpose node. As a result, if the uncorrectable data attachedwith the poisoning data passes through the general-purpose node, thegeneral-purpose node is excessively pointed out as an under-suspicioncomponent, resulting in a problem of causing a necessity for an extraexchange of the component.

It is an object of the present invention to provide a technology fordistinguishing whether or not, when the general-purpose node detects theuncorrectable error, the poisoning data is attached to the uncorrectabledata passing through the general-purpose node.

The present invention adopts the following means in order to solve theproblems. Namely, according to the present invention, a control devicemanaging a plurality of nodes transmitting and receiving data containingan error correcting code, comprises means accepting, when any one of thenodes detects an uncorrectable error from the data containing the errorcorrecting code, a signal transmitted by the node detecting the error,means judging from a record of the detection of a first node, whenaccepting the signal from a second node receiving data transmitted bythe first node, whether or not the first node has detected theuncorrectable error from the data transmitted to the second node, andmeans stopping, when the first node has detected the uncorrectable errorfrom the data transmitted to the second node, a process attributed tothe acceptance of the signal from the second node. With thisconfiguration, when judging from the record of the detection of thefirst node that the uncorrectable error is detected from the datatransmitted by the first node, the signal accepted from the second nodecan be recognized as being attributed to the first node's transmittingthe data containing the uncorrectable error to the second node. As aresult, the uncorrectable error contained in the data transmitted andreceived between the first node and the second node can be recognized tobe none of the uncorrectable error occurred due to the second node bystopping the process attributed to the acceptance of the signal from thesecond node.

Further, the control device according to the present invention mayfurther comprise means controlling a display device that displaysdetection of the uncorrectable error detected by any one of the nodes,wherein the process attributed to the signal acceptance may be a processof displaying, when accepting the signal from the second node, thedetection of the uncorrectable error detected by the second node on thedisplay device. With this configuration, it is possible to disable thedisplay device to display the detection of the uncorrectable error ofthe second node due to the first node's transmitting the data containingthe uncorrectable error to the second node.

Still further, according to the present invention, a node devicecooperating with a control device managing a plurality of nodesincluding a self-node, comprises means transmitting and receiving datacontaining an error correcting code to and from another node, meansconverting, when detecting an uncorrectable error from data transmittedto another node, the error correcting code contained in the data intopoisoning data having a value other than values that the errorcorrecting code can take, and record control means recording, when thetransmitting/receiving means transmits the data containing the poisoningdata to another node, a record of the transmission of the poisoning datain recording means referable from the control device. With thisconfiguration, the control device refers to the record of thetransmission of the poisoning data that is recorded in the recodingmeans, thereby making it possible to recognize that the data containingthe poisoning data has been transmitted to another node.

Yet further, the present invention may also be a method by which acomputer, other devices, other machines, etc execute the processesdescribed above. Moreover, the present invention may also be a programfor making the computer, other devices, other machines, etc actualizethe functions described above. Furthermore, the present invention mayalso be a recording medium recorded with such a program that is readableby the computer etc.

According to the present invention, it is possible to distinguish, whenthe general-purpose node detects the uncorrectable error, whether or notthe poisoning data is attached to the uncorrectable data passing throughthe general-purpose node.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an explanatory diagram showing an operation of a conventionaluncorrectable error detection system.

FIG. 2 is an explanatory diagram of the operation of the system in thepresent embodiment.

FIG. 3 is an explanatory diagram of an operation of how a POISONdetector 12 of an existing node F sets a bit in a register 13.

FIG. 4 is a diagram showing an example of a system configuration in thepresent embodiment.

FIG. 5 is an operation flowchart of the system in the presentembodiment.

DETAILED DESCRIPTION OF THE INVENTION

A system according to a best mode (which will hereinafter be termed anembodiment) for carrying out the present invention will hereinafter bedescribed with reference to the drawings. A configuration in thefollowing embodiment is an exemplification, and the present invention isnot limited to the configuration in the embodiments.

FIG. 2 is an explanatory diagram of an operation of the system in thepresent embodiment. The system in the present embodiment includesexisting nodes E, F and H each capable of distinguishing whether dataflowing through a self-node is attached with poisoning data or not(capable of recognizing the poisoning data attached to uncorrectabledata), and a general-purpose node G incapable of distinguishing whetherthe data flowing through the self-node is attached with the poisoningdata or not (incapable of recognizing the poisoning data attached to theuncorrectable data). An assumption in FIG. 2 is a case of adding thegeneral-purpose node G to the system including the plurality of existingnodes.

The system in the present embodiment further includes a firmware hub 2that accepts interrupt notification from the general-purpose node G, amanagement unit 3 that manages the whole system in the presentembodiment, a display unit 4 that displays a position where anuncorrectable error is detected, and an information aggregating unit 5that aggregates all of uncorrectable error occurrence information aboutthe uncorrectable errors occurred in the system in the presentembodiment.

The firmware hub 2 internally has a CPU (Central Processing Unit), a RAM(Random Access Memory), etc. Then, the CPU included in the firmware hub2 executes a variety of processes according to a firmware program storedon the RAM provided in the firmware hub 2. The management unit 3internally has the CPU, the RAM, etc. Then, the CPU included in themanagement unit 3 executes a variety of processes according to a programstored on the RAM provided in the management unit 3. The firmware hub 2and the management unit 3 correspond to a control device according tothe present invention.

The information aggregating unit 5 internally has a storage device suchas the RAM and a ROM (Read Only Memory). The storage device provided inthe information aggregating unit 5 is stored with the uncorrectableerror occurrence information.

The display unit 4 includes a display device constructed of, e.g., a CRT(Cathode Ray Tube), a liquid crystal display, a plasma display, etc, andalso an output device constructed of a voice output device such as aspeaker, a printer device and so on.

The existing node E and the existing node F are connected to each othervia a bus 6. The existing node F and the general-purpose node G areconnected to each other via a bus 7. The general-purpose node G and theexisting node H are connected to each other via a bus 8. Further, eachof the existing nodes E, F and H internally has a transmitting unit 9, areceiving unit 10, a converting unit 11, a POISON detector 12 and aregister 13. In FIG. 2, illustrations of the transmitting unit 9, thereceiving unit 10, the converting unit 11, the POISON detector 12 andthe register 13, which are provided in each of the existing nodes E andH, are omitted.

The transmitting unit 9 transmits the date received from another node tostill another node. The receiving unit 10 receives the data from anothernode. The converting unit 11, when receiving the uncorrectable data,converts the ECC attached to the uncorrectable data into the poisoningdata. The POISON detector 12 detects whether the transmitting unit 9transmits the poisoning data or not. The register 13 is recorded with aresult of the detection by the POISON detector 12.

The general-purpose node G internally has the unillustrated transmittingunit, receiving unit and detector. The receiving unit of thegeneral-purpose node G receives the data transmitted by the existingnode F. The transmitting unit of the general-purpose node G transmitsthe data to the existing node H. The detector of the general-purposenode G, when the transmitting unit of the general-purpose node Gtransmits the uncorrectable data or the poisoning data to the existingnode H, detects the uncorrectable error. Namely, the detector of thegeneral-purpose node G, when the uncorrectable or the poisoning datapasses through the transmitting unit of the general-purpose node G,detects the uncorrectable error.

The existing node F and the firmware hub 2 are connected to each othervia a bus 14. Further, the existing node E and the existing node H areeach connected to the firmware hub 2 via an unillustrated bus.

Moreover, the general-purpose node G and the firmware hub 2 areconnected to each other via a bus 15. The firmware hub 2 is connectedvia a bus 16 to the management unit 3. The management unit 3 isconnected via a bus 17 to the display unit 4. The firmware hub 2 and theinformation aggregating unit 5 are connected to each other via a bus 18.

Further, the existing node E, the existing node F, the general-purposenode G and the existing node H are each connected via unillustratedbuses to the information aggregating unit 5. Therefore, the informationaggregating unit 5 aggregates pieces of information about theuncorrectable errors occurred in the existing node E, the existing nodeF, the general-purpose node G, the existing node H, the bus 6, the bus 7and the bus 8.

Given next is an explanation of a system operation in the presentembodiment in a case where the uncorrectable error occurs. If theuncorrectable error occurs in the bus 6 between the existing node E andthe existing node F (which is represented by Occurrence of UE (1) inFIG. 2), the existing node F receives the data, as the uncorrectabledata, transmitted by the existing node E. In this case, the existingnode F detects the uncorrectable error (Detection of UE (1) in FIG. 2).Then, the existing node F executes a poisoning process about thereceived uncorrectable data.

The ECC (error correcting code) is attached to the uncorrectable datareceived from the existing node E. In the case of executing thepoisoning process about the uncorrectable data, the existing node Fconverts the ECC attached to the uncorrectable data into the poisoningdata. The poisoning data is unique data recognizable by the existingnode E, the existing node F and the existing node F. Further, thepoisoning data is converted into a value that is not overlapped with theECC. Namely, the poisoning data is converted into a value other thanvalues that can be taken by the ECC.

In the present embodiment, after executing the poisoning process aboutthe uncorrectable data, the ECC is not attached to this uncorrectabledata. Moreover, in the present embodiment, when the data to betransmitted and received takes 128 bits, the ECC is set to 16 bits. Thevalue of the data and the value of the ECC in the present embodiment areexemplifications, and the data and the ECC according to the presentinvention are not limited to these values.

The existing node F transmits the poisoning data to the general-purposenode G via the bus 7. When the transmitting unit 9 of the existing nodeF has transmitted the poisoning data, the POISON detector 12 detects thetransmission of the poisoning data. Namely, the POISON detector 12detects that the poisoning data has passed through the existing node F.Then, the POISON detector 12 sets a bit representing the passage of thepoisoning data in the register 13.

Herein, an operation of setting the bit in the register 13 by the POISONdetector 12 of the existing node F will be explained with reference toFIG. 3. As shown in FIG. 3, when the data is inputted to the existingnode F, a poisoning data detecting operation is carried out.

In FIG. 3, when the uncorrectable error occurs on the data input side ofthe existing node F (which is represented by Occurrence of UE (1) inFIG. 3), the existing node F executes a poisoning process about theinputted uncorrectable data. The POISON detector 12 and the register 13are provided in positions just anterior to the data output of theexisting node F. Therefore, the POISON detector 12 detects that thepoisoning data has been transmitted by the transmitting unit 9. Namely,the POISON detector 12 detects that the poisoning data has passedthrough the transmitting unit 9.

The POISON detector 12 detecting that the poisoning data has passedthrough the transmitting unit 9, sets “1” in a po bit of the register13. The po bit of the register 13 is defined as a bit representing thepassage of the poisoning data. “0” is set as an initial value in the pobit of the register 13.

Referring back to FIG. 2, the system operation in the present embodimentwill be described. As illustrated in FIG. 2, the existing node F, whichhas executed the poisoning process about the uncorrectable data,transmits the poisoning data to the general-purpose node G. In thiscase, the existing node F transmits a data packet containing thepoisoning data to the general-purpose node G.

The general-purpose node G is incapable of recognizing the poisoningdata attached to the uncorrectable data. Hence, the general-purpose nodeG, when transmitting the poisoning data to the existing node H, detectsthe uncorrectable error (represented by Detection of UE (2) in FIG. 2).The existing node H is capable of recognizing the poisoning dataattached to the uncorrectable data. Therefore, the existing node H, evenwhen receiving the uncorrectable data attached with the poisoning data,does not detect the uncorrectable error.

The general-purpose node G detects the uncorrectable error and givesinterrupt notification to the firmware hub 2. The firmware hub 2receiving the interrupt notification refers to the register 13 of theexisting node F.

The firmware hub 2, in the case of referring to the register 13 of theexisting node F, queries the information aggregating unit 5 about theuncorrectable error occurrence information. The information aggregatingunit 5 aggregates all of the uncorrectable error occurrence informationof the uncorrectable errors occurred in the system. To be specific, theinformation aggregating unit 5 is connected via the buses to all of thenodes existing in the system and is recorded with pieces of positioninformation of all of the nodes existing in the system. Therefore, ifthe uncorrectable error is detected in any one of the nodes existing inthe system, the information aggregating unit 5 gets recorded with theposition information of the node in which the uncorrectable is detected.

The firmware hub 2 queries the information aggregating unit 5 about theuncorrectable error occurrence information, thereby acquiring theposition information of the existing node F in which the uncorrectableerror is detected. Then, the firmware hub 2 acquiring the positioninformation of the existing node F refers to the register 13 of theexisting node F.

The firmware hub 2, when confirming that “1” is set in the po bit of theregister 13 of the existing node F, notifies the management unit 3 that“1” is set in the po bit of the register 13 of the existing node F. Themanagement unit 3, when receiving from the firmware hub 2 thenotification showing that “1” is set in the po bit of the register 13 ofthe existing node F, controls the display unit 4 not to display theinformation showing the uncorrectable error detected by thegeneral-purpose node G. Namely, the management unit 3 outputs, via a bus17, a control signal for displaying none of the position of thegeneral-purpose node G that has detected the uncorrectable error.

The display unit 4 displays the position of the general-purpose node Gthat has detected the uncorrectable error. The management unit 3controls the display unit 4, thereby disabling the display unit 4 todisplay that the general-purpose node G has detected the uncorrectableerror due to the general-purpose node G's receiving the poisoning data.

On the other hand, the firmware hub 2, when confirming that “0” is setin the po bit of the register 13 of the existing node F, notifies themanagement unit 3 that “0” is set in the po bit of the register 13 ofthe existing node F. The management unit 3, when receiving from thefirmware hub 2 the notification saying that “0” is set in the po bit ofthe register 13 of the existing node F, controls the display unit 4 todisplay the information showing the uncorrectable error detected by thegeneral-purpose node G. Namely, the management unit 3 outputs, via thebus 17, the control signal for displaying the position of thegeneral-purpose node G that has detected the uncorrectable error.

If the uncorrectable error occurs in the bus 7 via which the existingnode F and the general-purpose node G are connected to each other, theuncorrectable data received by the general-purpose node G does not passthrough the existing node F. Namely, the uncorrectable data received bythe general-purpose node G does not undergo the poisoning process by theexisting node F. Therefore, the po bit of the register 13 provided inthe existing node F is in a status of the initial value “0”.

The present embodiment has exemplified the case where the uncorrectableerror occurs in the bus 6 connecting the existing node E and theexisting node F to each other, and also exemplified the case theuncorrectable error occurs in the bus 7 connecting the existing node Fand the general-purpose node G to each other. The occurrence positionsof the uncorrectable errors are just exemplifications, and, for example,there is a case where the uncorrectable error might occur in theexisting node F. In this case also, in the same way as in the case wherethe uncorrectable error occurs in the bus 6 connecting the existing nodeE and the existing node F to each other, the converting unit 11 of theexisting node F executes the poisoning process about the uncorrectabledata that is to be transmitted to the general-purpose node G. As aresult, the poisoning data is attached to the uncorrectable datatransmitted by the existing node F to the general-purpose node G. Hence,when the transmitting unit 9 transmits the poisoning data, “1” is set inthe po bit of the register 13 provided in the existing node F.

Furthermore, for instance, if the uncorrectable error occurs in thegeneral-purpose node G, the data transmitted by the general-purpose nodeG to the existing node H is the uncorrectable data. In this case, theuncorrectable data transmitted by the general-purpose node G does notpass through the existing node F. Accordingly, in the same way as in thecase where the uncorrectable error occurs in the bus 7 connecting theexisting node F and the general-purpose node G to each other, the po bitof the register 13 provided in the existing node F is in the status ofthe initial value “0”. When the general-purpose node G transmits theuncorrectable data to the existing node H, the general-purpose node Gdetects the uncorrectable error.

Moreover, the present embodiment has exemplified the system includingthe display unit 4, however, a system having none of the display unit 4may also be available. For example, the display unit 4 may be providedoutside the system by changing the bus 17 shown in FIG. 2 to an externalinterface. The external interface with the Internet or Intranet can beused.

FIG. 4 is a diagram showing an example of a system configuration in thepresent embodiment. An address flow and a data flow in the presentembodiment will be explained with reference to FIG. 4.

To begin with, the address flow in the present embodiment will beexplained. The CPU 21 issues a read request to a north bridge 22 (1).The north bridge 22 transmits the address information to a crossbarswitch 23 for an address bus (2). The crossbar switch 23 for the addressbus transmits the address information to a south bridge 24 (3). Thesouth bridge 24 transmits the address information to a PCI Express chip25 (4). The PCI Express chip 25 transmits the address information to aPCI-BOX 26 (5).

Next, the data flow in the present embodiment will be explained. ThePCI-BOX 26 receiving the address information reads the datacorresponding to the address from an unillustrated PCI device connectedto the PCI-BOX 26, and transmits the readout data to the PCI Expresschip 25 (6). The PCI Express chip 25 transmits the data to the southbridge 24 (7). The south bridge 24 sends the data to a crossbar switch27 for a data bus (8). The crossbar switch 27 for the data bus transmitsthe data to a memory controller 28 (9). The memory controller 28transmits the data to the north bridge 22 (10). The north bridge 22sends the data to the CPU 21. The CPU 21 receives the read data, therebycompleting the read request (11).

The CPU 21, the north bridge 22, the south bridge 24, the PCI Expresschip 25, the PCI-BOX 26, the crossbar switch 27 for the data bus and thememory controller 28, which are illustrated in FIG. 4, correspond to theexisting node E, the existing node F, the general-purpose node G and theexisting node H shown in FIGS. 2 and 3. Further, each of the northbridge 22, the south bridge 24, the PCI Express chip 25, the crossbarswitch 27 for the data bus and the memory controller 28 includes thePOISON detector 12 shown in FIGS. 2 and 3. These schemes ofconfiguration are exemplifications, and the configuration in the presentembodiment is not limited to these schemes of configuration. Further,the system in the present embodiment can be actualized as an LSIsubstrate mounted with an LSI (Large Scale Integration).

In the present embodiment, the ECC is attached to the data stored in thePCI device. Further, each of the CPU 21, the north bridge 22, the southbridge 24, the PCI Express chip 25, the PCI-BOX 26, the crossbar switch27 for the data bus and the memory controller 28, which are illustratedin FIG. 4, has a function of attaching the ECCs. It is thereforepossible to attach the ECCs taking different formats from the ECCattached to the data stored in the PCI device.

FIG. 5 is an operation flowchart of the system in the presentembodiment. FIG. 5 illustrates how the system operates after thegeneral-purpose node G shown in FIG. 2 has received the uncorrectabledata from the existing node F. The general-purpose node G receiving theuncorrectable data from the existing node F, on the occasion oftransmitting the uncorrectable data to the existing node H, detects theuncorrectable error (S501) Next, the general-purpose node G notifies thefirmware hub 2 of an interrupt signal (S502). Then, the firmware hub 2refers to the register 13 of the existing node F and judges whether “1”is set in the po bit of the register 13 or not (S503).

When “1” is set in the po bit of the register 13 of the existing node F,the firmware hub 2 notifies the management unit 3 that “1” is set in thepo bit of the register 13 of the existing node F. The management unit 3recognizes that the poisoning data is attached to the uncorrectable datawhich is to be transmitted by the general-purpose node G (S504).

Thus, when the management unit 3 recognizes that the poisoning data isattached to the uncorrectable data which is to be transmitted by thegeneral-purpose node G, it is judged that the detection of theuncorrectable error by the general-purpose node G is attributed toneither a fault in the general-purpose node G nor a fault in the bus 7connected to the general-purpose node G. Namely, it can be judged thatthe general-purpose node G has transmitted the uncorrectable dataattached with the poisoning data due to the occurrence of the fault inany one of the nodes or the buses within the system.

While on the other hand, if “1” is not set in the po bit of the register13 of the existing node F (if “0” is set in the po bit of the register13 of the existing node F), the firmware hub 2 notifies the managementunit 3 that “1” is not set in the po bit of the register 13 of theexisting node F. The management unit 3 recognizes that the poisoningdata is not attached to the uncorrectable data which is to betransmitted by the general-purpose node G (S505).

Thus, when the management unit 3 recognizes that the poisoning data isnot attached to the uncorrectable data which is to be transmitted by thegeneral-purpose node G, it is judged that the detection of theuncorrectable error by the general-purpose node G is attributed to thefault in the general-purpose node G or the fault in the bus 7 connectedto the general-purpose node G.

According to the present embodiment, when the firmware hub 2 receivesthe interrupt notification from the general-purpose node G, the firmwarehub 2 refers to the po bit of the register 13 of the existing node F.When the firmware hub 2 recognizes that “1” is set in the Po bit of theregister 13 of the existing node F, it can be judged that theuncorrectable error occurs in a place other than the general-purposenode G and the bus 7 connected to the general-purpose node G. Namely, itcan be judged that the fault occurs in neither the general-purpose nodeG nor the bus 7 connected to the general-purpose node G.

Accordingly, even when the uncorrectable data is detected on such anoccasion that the general-purpose node G transmits the uncorrectabledata attached with the poisoning data, the general-purpose node G andthe bus 7 connected to the general-purpose node G can be prevented frombeing excessively pointed out as under-suspicion components. As aresult, it is possible to prevent extra exchanges of the general-purposenode G and the bus 7 connected to the general-purpose node G.

MODIFIED EXAMPLE

The embodiment has exemplified the configuration, wherein the managementunit 3 controls the display unit 4, thereby disabling the display unit 4to display the detection of the uncorrectable error by thegeneral-purpose node G due to the general-purpose node G's transmittingthe uncorrectable data attached with the poisoning data (which willhereinafter be termed “the detection of a ripple error”). All of theuncorrectable errors detected by the general-purpose node G can be alsodisplayed on the display unit 4.

In this case, an available scheme is that the management unit 3 controlsthe display unit 4, thereby displaying, on the display unit 4 in adifferent modes, the detection of the uncorrectable error by thegeneral-purpose node G (which will hereinafter be referred to as thedetection of the error due to the fault in the general-purpose node etc)due to the passage of the uncorrectable data attached with none of thepoisoning data through the general-purpose node G and also the detectionof the ripple error. To be specifics, the available scheme is that thedetection of the ripple error is displayed on the display unit 4, andthe detection of the error due to the fault in the general-purpose nodeetc is displayed on the display unit 4 in the distinguishable displaymode from the mode of displaying the detection of the ripple error.

The detection of the error due to the fault in the general-purpose nodeetc and the detection of the ripple error are displayed on the displayunit 4 in the different modes, thereby making it possible to recognizethe detection of the ripple error and to prevent the general-purposenode G detecting the ripple error and the bus 7 connected to thegeneral-purpose node G from being excessively pointed out as theunder-suspicion components.

Moreover, IP addresses are assigned to a personal computer, a mobileterminal, etc that are each mounted with the LSI substrate including thepresent system, whereby Web management can be attained. Namely, thepersonal computer, the mobile terminal, etc that are each mounted withthe LSI substrate including the present system are connected to a servervia the external interface, whereby a user can recognize the detectionof the uncorrectable error on the Web. The management by the server onthe Web can be actualized by installing Web management software into theserver. Further, the server can be actualized by general types ofpersonal computer, workstation, etc. In this case, the server isconnected to the display unit 4, whereby the uncorrectable errordetection information received by the server is decrypted by a Browserand then displayed on the display unit 4.

Moreover, the existing node E, the existing node F, the general-purposenode G and the existing node H in the present embodiment can be replacedby the network-communication-enabled personal computer, mobile terminal,etc. In this case, the bus 6, the bus 7 and the bus 8 are replaced bythe network-communication-enabled signal lines, the Internet or theIntranet, whereby the system employing the network can detect theuncorrectable error.

<Computer Readable Recording Medium>

It is possible to record a program which causes a computer to implementany of the functions described above on a computer readable recordingmedium. By causing the computer to read in the program from therecording medium and execute it, the function thereof can be provided.The computer readable recording medium mentioned herein indicates arecording medium which stores information such as data and a program byan electric, magnetic, optical, mechanical, or chemical operation andallows the stored information to be read from the computer. Of suchrecording media, those detachable from the computer include, e.g., aflexible disk, a magneto-optical disk, a CD-ROM, a CD-R/W, a DVD, a DAT,an 8-mm tape, and a memory card. Of such recording media, those fixed tothe computer include a hard disk and a ROM (Read Only Memory)

<Others>

The disclosures of Japanese patent application No. JP2006-223346 filedon Aug. 18, 2006 including the specification, drawings and abstract areincorporated herein by reference.

1. A control device managing a plurality of nodes transmitting andreceiving data containing an error correcting code, comprising: anaccepting unit for accepting a signal transmitted from any one of theplurality of nodes that has detected an uncorrectable error from datacontaining the error correcting code; a judging unit for judging, if theaccepting unit has accepted the signal from a second node that hasreceived data transmitted from a first node, whether or not the firstnode has detected the uncorrectable error from the data transmitted tothe second node based on the detection record of the first node; and astopping unit for stopping a process attributed to the reception of thesignal from the second node if the judging unit has judged that thefirst node has detected the uncorrectable error from the datatransmitted to the second node.
 2. The control device according to claim1, further comprising a controlling unit for controlling a displaydevice to display information corresponding to a detection of theuncorrectable error detected by any one of the plurality of nodes,wherein the process attributed to the signal reception is a process ofdisplaying the detection of the uncorrectable error detected by thesecond node on the display device; and if the judging unit has judgedthat the first node has detected the uncorrectable error, a display ofinformation of the detection of the uncorrectable error by the secondnode is not operated.
 3. A node device cooperating with a control devicemanaging a plurality of node devices, comprising: atransmitting/receiving unit for transmitting and receiving datacontaining an error correcting code to and from another node; aconverting unit for converting an error correcting code contained indata to be transmitted to the another node into poisoning data having avalue other than a value that the error correcting code can take if ancorrectable error is detected from the data to be transmitted to theanother node; a record control unit for recording a record oftransmission of the poisoning data into a recording unit that isreferable from the control device if the transmitting/receiving unittransmits the data containing the poisoning data to the another node;and a detecting unit for detecting an uncorrectable error from datatransmitted to a first node, wherein the detecting unit, if the datareceived from a second node includes the poisoning data, does not detectthe uncorrectable error with respect to the data transmitted to thefirst node.
 4. A control method of a control device managing a pluralityof nodes transmitting and receiving data containing an error correctingcode, comprising: receiving a signal from a first node among the nodesthat has detected an uncorrectable error in data that the first node hasreceived; judging whether a second node that transmitted the data to thefirst node has detected the uncorrectable error in the transmitted dataor not if the signal from the first node is received; and operating aprocess corresponding to the signal received from the first node ifhaving received the signal, while not operating the process in the caseif it is judged that the second node has detected the uncorrectableerror.
 5. The control method of a control device according to claim 4,further comprising: displaying information corresponding to thedetection of an uncorrectable error by any one of the plurality of nodesupon receiving the signal from the node, wherein if it is judged thatthe second node has detected the uncorrectable error, a display ofinformation that the first node has detected the uncorrectable error isnot operated.
 6. A non-transitory, computer readable medium recordedwith a control program making a computer execute: receiving a signalfrom a first node among the nodes that has detected an uncorrectableerror in data that the first node has received; judging whether a secondnode that transmitted the data to the first node has detected theuncorrectable error in the transmitted data or not if the signal fromthe first node is received; and operating a process corresponding to thesignal received from the first node if the signal is received, while notoperating the process in the case where it is judged that the secondnode has detected the uncorrectable error in the data transmitted to thefirst node.
 7. The non-transitory, computer readable according to claim6, wherein the process corresponding to the signal is a process fordisplaying information corresponding to the detection of anuncorrectable error by any node, the information indicating that thefirst node has detected the uncorrectable error is not displayed even ifsignal is received from the first node if it is judged that the secondnode has detected the uncorrectable error.
 8. A control device connectedto a display device, for managing a plurality of nodes transmitting andreceiving data containing an error correcting code, comprising: areceiving unit for receiving a signal from any node indicating that thenode has detected an uncorrectable error in data received from anothernode; a judging unit for judging whether the another node has detectedan uncorrectable error in data transmitted to the node by referring toan error detection record of the another node, if the receiving unit hasreceived the signal from the node; and a control unit for controlling,upon the receiving unit has received the signal, the display unit todisplay information indicating that the node has detected theuncorrectable error if the judging unit judged that the another node hasnot detected the uncorrectable error, and not to display the informationif the judging unit judged that the another node has detected theuncorrectable error in the data transmitted to the node.
 9. The controldevice according to claim 8, wherein the judging unit judges whether theanother node has detected the uncorrectable error if the receiving unithas received the signal from a type of node that cannot detect apoisoning data contained in the received data, the poisoning data isdata in which any node that has detected the uncorrectable error hasgenerated by converting the error correcting the error correcting codecontained in the data the uncorrectable error is detected into a datahaving a value different from the error correcting code.